The time compression of audio information into video bandwidth information and the further processing of the time compressed information into pseudo video information of a format comparable to a television line is disclosed in U.S. Pat. No. 3,789,137, issued Jan. 29, 1974, assigned to the assignee of the present invention and incorporated herein by reference. This technique permits video transmission of many minutes of audio information in a few seconds. In this system, a single frame or field of video information is recorded on a separate recording track of a magnetic medium via a single moving head immediately prior to the recording of the accompanying audio information. In this system, each video frame is displayed for the period of time necessary to play back the audio track immediately following it and as such does not provide for changes in displayed video information during the playback of an audio track.
A suitable technique for achieving the recording of audio and video tracks is described in U.S. Pat. No. 3,878,560, issued Apr. 15, 1974 and assigned to the assignee of the present invention.
There is disclosed in the above-identified copending related application, Ser. No. 637,551, an improved audio-video program recording technique which provides for the interleaved recording of video (single frames or fields) and audio fields or frames, in which time compressed audio segments or audio lines are recorded on separate sections or tracks of a storage medium, such as a video or magnetic storage media leaving blank sections or tracks for the later insertion of associated video information in response to video change signals inserted in one or more of the audio lines. The term audio lines refers to the time compressed audio lines developed in accordance with the teachings of U.S. Pat. No. 3,789,137 wherein each audio segments is comparable to a television line.
The video change signals recorded in selected audio lines control the video displayed in conjunction with the audio information during playback of the audio-video program.